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'Dicey Dice' printed from https://nrich.maths.org/
You can use common sense for simple comparisons between dice, but
where the relative probabilities are not obvious you can use the
formula for conditional expectation:
$$
P(A> B) = P(A> B|A=1)P(A=1)+\dots + P(A>
B|A=6)P(A=6)
$$